Microwaving the heart

Abstract

Atrial fibrillation (AF) is a chaotic (and lethal) cardiac rhythm disorder that profoundly affects the cardiovascular performance. Surgical therapeutic intervention has been the principal method of treatment in these cases. The standard method has been the scalpel based "maze" cut and sew procedure. The method aims at interrupting the circular electrical patterns that are responsible for the arrhythmia. Strategic placement of incisions in both atria terminates the formation and the conduction of errant electrical impulses, and channels the normal electrical impulse in one direction. Scar tissue generated by the incisions permanently blocks the paths of the impulses that cause AF, thus eradicating the arrhythmia. Microwave cardiac ablation is a relatively new concept for the clinical treatment of cardiac arrhythmias. It is a procedure in which oscillating electromagnetic energy is delivered to the myocardium (the heart muscle), via a probe, to create thermal lesions. The frequencies typically used for microwave medical ablation are 915 MHz or 2.45 GHz. The thermal lesions are relied upon to disrupt or eliminate the conduction pathways supporting arrythmia. This relatively new technology has accrued an impressive clinical history in terms of biophysical and clinical efficacy, safety and surgeons' satisfaction.